We studied the use of forest fragments by five medium-sized carnivore species in 280 forest fragments on the two Iberian plateaus. We looked for indirect evidence (faeces, tracks, dens) of fragment use (occurrence) by the species and analysed whether the occurrence could be related to four groups of variables: local (vegetation structure and patch size), landscape (distance to possible colonisation sources), regional (fragment location on the northern or southern plateau) and the vegetation type of the fragments. We analysed the differential response of species according to their life-history and behavioural traits. The relationship between use by each species and the factors studied was analysed using stepwise logistic regressions. Results indicate that three factors are crucial to explain fragment use: fragment size, geographic location and vegetation type. Large fragments are used more than smaller ones, the northern plateau is more suitable than the southern plateau, and holm oak and broad-leaved oak forest are more used than pine woods. the effects and magnitude varied slightly among species, depending on habitat requirements or life-history traits. Data indicate that conservation strategies in fragmented environments must take into account elements functioning at different spatial scales, and that it is essential to consider each case within a characteristic regional context. Palabras clave: Biodiversity, Forest, Fragmentation, Mammal